Update documentation for write_hint

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index a098a771189f34b2354cad1ccf6616fc4bcf1a96..e544634009ef0907dbd2ad0345af45c5326008f9 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -54,56 +54,66 @@ Command line options
 
 .. option:: --debug=type
 
 
 .. option:: --debug=type
 

-    Enable verbose tracing of various fio actions.  May be ``all`` for all types
-    or individual types separated by a comma (e.g. ``--debug=file,mem`` will
-    enable file and memory debugging).  Currently, additional logging is
-    available for:
+       Enable verbose tracing of various fio actions.  May be ``all`` for all types
+       or individual types separated by a comma (e.g. ``--debug=file,mem`` will
+       enable file and memory debugging).  Currently, additional logging is
+       available for:

 
 

-    *process*
+       *process*

                        Dump info related to processes.
                        Dump info related to processes.

-    *file*
+       *file*

                        Dump info related to file actions.
                        Dump info related to file actions.

-    *io*
+       *io*

                        Dump info related to I/O queuing.
                        Dump info related to I/O queuing.

-    *mem*
+       *mem*

                        Dump info related to memory allocations.
                        Dump info related to memory allocations.

-    *blktrace*
+       *blktrace*

                        Dump info related to blktrace setup.
                        Dump info related to blktrace setup.

-    *verify*
+       *verify*

                        Dump info related to I/O verification.
                        Dump info related to I/O verification.

-    *all*
+       *all*

                        Enable all debug options.
                        Enable all debug options.

-    *random*
+       *random*

                        Dump info related to random offset generation.
                        Dump info related to random offset generation.

-    *parse*
+       *parse*

                        Dump info related to option matching and parsing.
                        Dump info related to option matching and parsing.

-    *diskutil*
+       *diskutil*

                        Dump info related to disk utilization updates.
                        Dump info related to disk utilization updates.

-    *job:x*
+       *job:x*

                        Dump info only related to job number x.
                        Dump info only related to job number x.

-    *mutex*
+       *mutex*

                        Dump info only related to mutex up/down ops.
                        Dump info only related to mutex up/down ops.

-    *profile*
+       *profile*

                        Dump info related to profile extensions.
                        Dump info related to profile extensions.

-    *time*
+       *time*

                        Dump info related to internal time keeping.
                        Dump info related to internal time keeping.

-    *net*
+       *net*

                        Dump info related to networking connections.
                        Dump info related to networking connections.

-    *rate*
+       *rate*

                        Dump info related to I/O rate switching.
                        Dump info related to I/O rate switching.

-    *compress*
+       *compress*

                        Dump info related to log compress/decompress.
                        Dump info related to log compress/decompress.

-    *?* or *help*
+       *?* or *help*

                        Show available debug options.
 
 .. option:: --parse-only
 
                        Show available debug options.
 
 .. option:: --parse-only
 

-    Parse options only, don\'t start any I/O.
+       Parse options only, don\'t start any I/O.

 
 .. option:: --output=filename
 
        Write output to file `filename`.
 
 
 .. option:: --output=filename
 
        Write output to file `filename`.
 

+.. option:: --output-format=type
+
+       Set the reporting format to `normal`, `terse`, `json`, or `json+`.  Multiple
+       formats can be selected, separated by a comma.  `terse` is a CSV based
+       format.  `json+` is like `json`, except it adds a full dump of the latency
+       buckets.
+
+.. option:: --runtime
+       Limit run time to runtime seconds.
+

 .. option:: --bandwidth-log
 
        Generate aggregate bandwidth logs.
 .. option:: --bandwidth-log
 
        Generate aggregate bandwidth logs.


@@ -114,16 +124,9 @@ Command line options
 
 .. option:: --append-terse
 
 
 .. option:: --append-terse
 

-    Print statistics in selected mode AND terse, semicolon-delimited format.
-    **deprecated**, use :option:`--output-format` instead to select multiple
-    formats.
-
-.. option:: --output-format=type
-
-       Set the reporting format to `normal`, `terse`, `json`, or `json+`.  Multiple
-       formats can be selected, separated by a comma.  `terse` is a CSV based
-       format.  `json+` is like `json`, except it adds a full dump of the latency
-       buckets.
+       Print statistics in selected mode AND terse, semicolon-delimited format.
+       **Deprecated**, use :option:`--output-format` instead to select multiple
+       formats.

 
 .. option:: --terse-version=type
 
 
 .. option:: --terse-version=type
 


@@ -131,7 +134,7 @@ Command line options
 
 .. option:: --version
 
 
 .. option:: --version
 

-       Print version info and exit.
+       Print version information and exit.

 
 .. option:: --help
 
 
 .. option:: --help
 


@@ -143,9 +146,9 @@ Command line options
 
 .. option:: --crctest=[test]
 
 
 .. option:: --crctest=[test]
 

-    Test the speed of the built-in checksumming functions. If no argument is
-    given all of them are tested. Alternatively, a comma separated list can be passed, in
-    which case the given ones are tested.
+       Test the speed of the built-in checksumming functions. If no argument is
+       given, all of them are tested. Alternatively, a comma separated list can
+       be passed, in which case the given ones are tested.

 
 .. option:: --cmdhelp=command
 
 
 .. option:: --cmdhelp=command
 


@@ -153,27 +156,27 @@ Command line options
 
 .. option:: --enghelp=[ioengine[,command]]
 
 
 .. option:: --enghelp=[ioengine[,command]]
 

-    List all commands defined by :option:`ioengine`, or print help for `command`
-    defined by :option:`ioengine`.  If no :option:`ioengine` is given, list all
-    available ioengines.
+       List all commands defined by :option:`ioengine`, or print help for `command`
+       defined by :option:`ioengine`.  If no :option:`ioengine` is given, list all
+       available ioengines.

 
 .. option:: --showcmd=jobfile
 
 
 .. option:: --showcmd=jobfile
 

-       Turn a job file into command line options.
+       Convert `jobfile` to a set of command-line options.

 
 .. option:: --readonly
 
 
 .. option:: --readonly
 

-    Turn on safety read-only checks, preventing writes.  The ``--readonly``
-    option is an extra safety guard to prevent users from accidentally starting
-    a write workload when that is not desired.  Fio will only write if
-    `rw=write/randwrite/rw/randrw` is given.  This extra safety net can be used
-    as an extra precaution as ``--readonly`` will also enable a write check in
-    the I/O engine core to prevent writes due to unknown user space bug(s).
+       Turn on safety read-only checks, preventing writes.  The ``--readonly``
+       option is an extra safety guard to prevent users from accidentally starting
+       a write workload when that is not desired.  Fio will only write if
+       `rw=write/randwrite/rw/randrw` is given.  This extra safety net can be used
+       as an extra precaution as ``--readonly`` will also enable a write check in
+       the I/O engine core to prevent writes due to unknown user space bug(s).

 
 .. option:: --eta=when
 
 
 .. option:: --eta=when
 

-       When real-time ETA estimate should be printed.  May be `always`, `never` or
-       `auto`.
+       Specifies when real-time ETA estimate should be printed.  `when` may be
+       `always`, `never` or `auto`.

 
 .. option:: --eta-newline=time
 
 
 .. option:: --eta-newline=time
 


@@ -187,48 +190,48 @@ Command line options
 
 .. option:: --section=name
 
 
 .. option:: --section=name
 

-    Only run specified section in job file.  Multiple sections can be specified.
-    The ``--section`` option allows one to combine related jobs into one file.
-    E.g. one job file could define light, moderate, and heavy sections. Tell
-    fio to run only the "heavy" section by giving ``--section=heavy``
-    command line option.  One can also specify the "write" operations in one
-    section and "verify" operation in another section.  The ``--section`` option
-    only applies to job sections.  The reserved *global* section is always
-    parsed and used.
+       Only run specified section `name` in job file.  Multiple sections can be specified.
+       The ``--section`` option allows one to combine related jobs into one file.
+       E.g. one job file could define light, moderate, and heavy sections. Tell
+       fio to run only the "heavy" section by giving ``--section=heavy``
+       command line option.  One can also specify the "write" operations in one
+       section and "verify" operation in another section.  The ``--section`` option
+       only applies to job sections.  The reserved *global* section is always
+       parsed and used.

 
 .. option:: --alloc-size=kb
 
 
 .. option:: --alloc-size=kb
 

-    Set the internal smalloc pool to this size in KiB.  The
-    ``--alloc-size`` switch allows one to use a larger pool size for smalloc.
-    If running large jobs with randommap enabled, fio can run out of memory.
-    Smalloc is an internal allocator for shared structures from a fixed size
-    memory pool and can grow to 16 pools. The pool size defaults to 16MiB.
+       Set the internal smalloc pool size to `kb` in KiB.  The
+       ``--alloc-size`` switch allows one to use a larger pool size for smalloc.
+       If running large jobs with randommap enabled, fio can run out of memory.
+       Smalloc is an internal allocator for shared structures from a fixed size
+       memory pool and can grow to 16 pools. The pool size defaults to 16MiB.

 
 

-    NOTE: While running :file:`.fio_smalloc.*` backing store files are visible
-    in :file:`/tmp`.
+       NOTE: While running :file:`.fio_smalloc.*` backing store files are visible
+       in :file:`/tmp`.

 
 .. option:: --warnings-fatal
 
 
 .. option:: --warnings-fatal
 

-    All fio parser warnings are fatal, causing fio to exit with an
-    error.
+       All fio parser warnings are fatal, causing fio to exit with an
+       error.

 
 .. option:: --max-jobs=nr
 
 
 .. option:: --max-jobs=nr
 

-       Maximum number of threads/processes to support.
+       Set the maximum number of threads/processes to support.

 
 .. option:: --server=args
 
 
 .. option:: --server=args
 

-    Start a backend server, with `args` specifying what to listen to.
-    See `Client/Server`_ section.
+       Start a backend server, with `args` specifying what to listen to.
+       See `Client/Server`_ section.

 
 .. option:: --daemonize=pidfile
 
 
 .. option:: --daemonize=pidfile
 

-    Background a fio server, writing the pid to the given `pidfile` file.
+       Background a fio server, writing the pid to the given `pidfile` file.

 
 .. option:: --client=hostname
 
 
 .. option:: --client=hostname
 

-    Instead of running the jobs locally, send and run them on the given host or
-    set of hosts.  See `Client/Server`_ section.
+       Instead of running the jobs locally, send and run them on the given host or
+       set of hosts.  See `Client/Server`_ section.

 
 .. option:: --remote-config=file
 
 
 .. option:: --remote-config=file
 


@@ -236,7 +239,7 @@ Command line options
 
 .. option:: --idle-prof=option
 
 
 .. option:: --idle-prof=option
 

-       Report CPU idleness. *option* is one of the following:
+       Report CPU idleness. `option` is one of the following:

 
                **calibrate**
                        Run unit work calibration only and exit.
 
                **calibrate**
                        Run unit work calibration only and exit.


@@ -445,7 +448,7 @@ automatically substituted with the current system values when the job is
 run. Simple math is also supported on these keywords, so you can perform actions
 like::
 
 run. Simple math is also supported on these keywords, so you can perform actions
 like::
 

-        size=8*$mb_memory
+       size=8*$mb_memory

 
 and get that properly expanded to 8 times the size of memory in the machine.
 
 
 and get that properly expanded to 8 times the size of memory in the machine.
 


@@ -474,7 +477,7 @@ Parameter types
 ~~~~~~~~~~~~~~~
 
 **str**
 ~~~~~~~~~~~~~~~
 
 **str**

-    String. This is a sequence of alpha characters.
+       String: A sequence of alphanumeric characters.

 
 **time**
        Integer with possible time suffix.  Without a unit value is interpreted as
 
 **time**
        Integer with possible time suffix.  Without a unit value is interpreted as


@@ -488,7 +491,7 @@ Parameter types
        Integer. A whole number value, which may contain an integer prefix
        and an integer suffix:
 
        Integer. A whole number value, which may contain an integer prefix
        and an integer suffix:
 

-        [*integer prefix*] **number** [*integer suffix*]
+       [*integer prefix*] **number** [*integer suffix*]

 
        The optional *integer prefix* specifies the number's base. The default
        is decimal. *0x* specifies hexadecimal.
 
        The optional *integer prefix* specifies the number's base. The default
        is decimal. *0x* specifies hexadecimal.


@@ -521,7 +524,7 @@ Parameter types
        compatibility with old scripts.  For example, 4k means 4096.
 
        For quantities of data, an optional unit of 'B' may be included
        compatibility with old scripts.  For example, 4k means 4096.
 
        For quantities of data, an optional unit of 'B' may be included

-       (e.g.,  'kB' is the same as 'k').
+       (e.g., 'kB' is the same as 'k').

 
        The *integer suffix* is not case sensitive (e.g., m/mi mean mebi/mega,
        not milli). 'b' and 'B' both mean byte, not bit.
 
        The *integer suffix* is not case sensitive (e.g., m/mi mean mebi/mega,
        not milli). 'b' and 'B' both mean byte, not bit.


@@ -853,10 +856,13 @@ Target file/device
                **pareto**
                        Use a *Pareto* distribution to decide what file to access.
 
                **pareto**
                        Use a *Pareto* distribution to decide what file to access.
 

-               **gauss**
+               **normal**

                        Use a *Gaussian* (normal) distribution to decide what file to
                        access.
 
                        Use a *Gaussian* (normal) distribution to decide what file to
                        access.
 

+               **gauss**
+                       Alias for normal.
+

        For *random*, *roundrobin*, and *sequential*, a postfix can be appended to
        tell fio how many I/Os to issue before switching to a new file. For example,
        specifying ``file_service_type=random:8`` would cause fio to issue
        For *random*, *roundrobin*, and *sequential*, a postfix can be appended to
        tell fio how many I/Os to issue before switching to a new file. For example,
        specifying ``file_service_type=random:8`` would cause fio to issue


@@ -1046,6 +1052,10 @@ I/O type
                **none**
                        Do not pre-allocate space.
 
                **none**
                        Do not pre-allocate space.
 

+               **native**
+                       Use a platform's native pre-allocation call but fall back to
+                       **none** behavior if it fails/is not implemented.
+

                **posix**
                        Pre-allocate via :manpage:`posix_fallocate(3)`.
 
                **posix**
                        Pre-allocate via :manpage:`posix_fallocate(3)`.
 


@@ -1060,8 +1070,9 @@ I/O type
                        Backward-compatible alias for **posix**.
 
        May not be available on all supported platforms. **keep** is only available
                        Backward-compatible alias for **posix**.
 
        May not be available on all supported platforms. **keep** is only available

-       on Linux. If using ZFS on Solaris this must be set to **none** because ZFS
-       doesn't support it. Default: **posix**.
+       on Linux. If using ZFS on Solaris this cannot be set to **posix**
+       because ZFS doesn't support pre-allocation. Default: **native** if any
+       pre-allocation methods are available, **none** if not.

 
 .. option:: fadvise_hint=str
 
 
 .. option:: fadvise_hint=str
 


@@ -1082,19 +1093,39 @@ I/O type
                **random**
                        Advise using **FADV_RANDOM**.
 
                **random**
                        Advise using **FADV_RANDOM**.
 

-.. option:: fadvise_stream=int
+.. option:: write_hint=str
+
+       Use :manpage:`fcntl(2)` to advise the kernel what life time to expect
+       from a write. Only supported on Linux, as of version 4.13. Accepted
+       values are:
+
+               **none**
+                       No particular life time associated with this file.
+
+               **short**
+                       Data written to this file has a short life time.
+
+               **medium**
+                       Data written to this file has a medium life time.
+
+               **long**
+                       Data written to this file has a long life time.

 
 

-       Use :manpage:`posix_fadvise(2)` to advise the kernel what stream ID the
-       writes issued belong to. Only supported on Linux. Note, this option may
-       change going forward.
+               **extreme**
+                       Data written to this file has a very long life time.
+
+       The values are all relative to each other, and no absolute meaning
+       should be associated with them.

 
 .. option:: offset=int
 
 
 .. option:: offset=int
 

-       Start I/O at the provided offset in the file, given as either a fixed size or
-       a percentage. If a percentage is given, the next ``blockalign``-ed offset
-       will be used. Data before the given offset will not be touched. This
+       Start I/O at the provided offset in the file, given as either a fixed size in
+       bytes or a percentage. If a percentage is given, the next ``blockalign``-ed
+       offset will be used. Data before the given offset will not be touched. This

        effectively caps the file size at `real_size - offset`. Can be combined with
        :option:`size` to constrain the start and end range of the I/O workload.
        effectively caps the file size at `real_size - offset`. Can be combined with
        :option:`size` to constrain the start and end range of the I/O workload.

+       A percentage can be specified by a number between 1 and 100 followed by '%',
+       for example, ``offset=20%`` to specify 20%.

 
 .. option:: offset_increment=int
 
 
 .. option:: offset_increment=int
 


@@ -1202,7 +1233,7 @@ I/O type
                **pareto**
                                Pareto distribution
 
                **pareto**
                                Pareto distribution
 

-               **gauss**
+               **normal**

                                Normal (Gaussian) distribution
 
                **zoned**
                                Normal (Gaussian) distribution
 
                **zoned**


@@ -1215,8 +1246,8 @@ I/O type
        values will yield in terms of hit rates.  If you wanted to use **zipf** with
        a `theta` of 1.2, you would use ``random_distribution=zipf:1.2`` as the
        option. If a non-uniform model is used, fio will disable use of the random
        values will yield in terms of hit rates.  If you wanted to use **zipf** with
        a `theta` of 1.2, you would use ``random_distribution=zipf:1.2`` as the
        option. If a non-uniform model is used, fio will disable use of the random

-       map. For the **gauss** distribution, a normal deviation is supplied as a
-       value between 0 and 100.
+       map. For the **normal** distribution, a normal (Gaussian) deviation is
+       supplied as a value between 0 and 100.

 
        For a **zoned** distribution, fio supports specifying percentages of I/O
        access that should fall within what range of the file or device. For
 
        For a **zoned** distribution, fio supports specifying percentages of I/O
        access that should fall within what range of the file or device. For


@@ -1749,7 +1780,7 @@ I/O engine
                        :file:`/dev/mtd0`). Discards are treated as erases. Depending on the
                        underlying device type, the I/O may have to go in a certain pattern,
                        e.g., on NAND, writing sequentially to erase blocks and discarding
                        :file:`/dev/mtd0`). Discards are treated as erases. Depending on the
                        underlying device type, the I/O may have to go in a certain pattern,
                        e.g., on NAND, writing sequentially to erase blocks and discarding

-                       before overwriting. The writetrim mode works well for this
+                       before overwriting. The `trimwrite` mode works well for this

                        constraint.
 
                **pmemblk**
                        constraint.
 
                **pmemblk**


@@ -2373,13 +2404,14 @@ Verification
                        header of each block.
 
                **crc32c**
                        header of each block.
 
                **crc32c**

-                       Use a crc32c sum of the data area and store it in the header of each
-                       block.
+                       Use a crc32c sum of the data area and store it in the header of
+                       each block. This will automatically use hardware acceleration
+                       (e.g. SSE4.2 on an x86 or CRC crypto extensions on ARM64) but will
+                       fall back to software crc32c if none is found. Generally the
+                       fatest checksum fio supports when hardware accelerated.

 
                **crc32c-intel**
 
                **crc32c-intel**

-                       Use hardware assisted crc32c calculation provided on SSE4.2 enabled
-                       processors. Falls back to regular software crc32c, if not supported
-                       by the system.
+                       Synonym for crc32c.

 
                **crc32**
                        Use a crc32 sum of the data area and store it in the header of each
 
                **crc32**
                        Use a crc32 sum of the data area and store it in the header of each


@@ -3322,7 +3354,7 @@ will be a disk utilization section.
 Below is a single line containing short names for each of the fields in the
 minimal output v3, separated by semicolons::
 
 Below is a single line containing short names for each of the fields in the
 minimal output v3, separated by semicolons::
 

-       terse_version_3;fio_version;jobname;groupid;error;read_kb;read_bandwidth;read_iops;read_runtime_ms;read_slat_min;read_slat_max;read_slat_mean;read_slat_dev;read_clat_max;read_clat_min;read_clat_mean;read_clat_dev;read_clat_pct01;read_clat_pct02;read_clat_pct03;read_clat_pct04;read_clat_pct05;read_clat_pct06;read_clat_pct07;read_clat_pct08;read_clat_pct09;read_clat_pct10;read_clat_pct11;read_clat_pct12;read_clat_pct13;read_clat_pct14;read_clat_pct15;read_clat_pct16;read_clat_pct17;read_clat_pct18;read_clat_pct19;read_clat_pct20;read_tlat_min;read_lat_max;read_lat_mean;read_lat_dev;read_bw_min;read_bw_max;read_bw_agg_pct;read_bw_mean;read_bw_dev;write_kb;write_bandwidth;write_iops;write_runtime_ms;write_slat_min;write_slat_max;write_slat_mean;write_slat_dev;write_clat_max;write_clat_min;write_clat_mean;write_clat_dev;write_clat_pct01;write_clat_pct02;write_clat_pct03;write_clat_pct04;write_clat_pct05;write_clat_pct06;write_clat_pct07;write_clat_pct08;write_clat_pct09;write_clat_pct10;write_clat_pct11;write_clat_pct12;write_clat_pct13;write_clat_pct14;write_clat_pct15;write_clat_pct16;write_clat_pct17;write_clat_pct18;write_clat_pct19;write_clat_pct20;write_tlat_min;write_lat_max;write_lat_mean;write_lat_dev;write_bw_min;write_bw_max;write_bw_agg_pct;write_bw_mean;write_bw_dev;cpu_user;cpu_sys;cpu_csw;cpu_mjf;pu_minf;iodepth_1;iodepth_2;iodepth_4;iodepth_8;iodepth_16;iodepth_32;iodepth_64;lat_2us;lat_4us;lat_10us;lat_20us;lat_50us;lat_100us;lat_250us;lat_500us;lat_750us;lat_1000us;lat_2ms;lat_4ms;lat_10ms;lat_20ms;lat_50ms;lat_100ms;lat_250ms;lat_500ms;lat_750ms;lat_1000ms;lat_2000ms;lat_over_2000ms;disk_name;disk_read_iops;disk_write_iops;disk_read_merges;disk_write_merges;disk_read_ticks;write_ticks;disk_queue_time;disk_util
+       terse_version_3;fio_version;jobname;groupid;error;read_kb;read_bandwidth;read_iops;read_runtime_ms;read_slat_min;read_slat_max;read_slat_mean;read_slat_dev;read_clat_min;read_clat_max;read_clat_mean;read_clat_dev;read_clat_pct01;read_clat_pct02;read_clat_pct03;read_clat_pct04;read_clat_pct05;read_clat_pct06;read_clat_pct07;read_clat_pct08;read_clat_pct09;read_clat_pct10;read_clat_pct11;read_clat_pct12;read_clat_pct13;read_clat_pct14;read_clat_pct15;read_clat_pct16;read_clat_pct17;read_clat_pct18;read_clat_pct19;read_clat_pct20;read_tlat_min;read_lat_max;read_lat_mean;read_lat_dev;read_bw_min;read_bw_max;read_bw_agg_pct;read_bw_mean;read_bw_dev;write_kb;write_bandwidth;write_iops;write_runtime_ms;write_slat_min;write_slat_max;write_slat_mean;write_slat_dev;write_clat_min;write_clat_max;write_clat_mean;write_clat_dev;write_clat_pct01;write_clat_pct02;write_clat_pct03;write_clat_pct04;write_clat_pct05;write_clat_pct06;write_clat_pct07;write_clat_pct08;write_clat_pct09;write_clat_pct10;write_clat_pct11;write_clat_pct12;write_clat_pct13;write_clat_pct14;write_clat_pct15;write_clat_pct16;write_clat_pct17;write_clat_pct18;write_clat_pct19;write_clat_pct20;write_tlat_min;write_lat_max;write_lat_mean;write_lat_dev;write_bw_min;write_bw_max;write_bw_agg_pct;write_bw_mean;write_bw_dev;cpu_user;cpu_sys;cpu_csw;cpu_mjf;cpu_minf;iodepth_1;iodepth_2;iodepth_4;iodepth_8;iodepth_16;iodepth_32;iodepth_64;lat_2us;lat_4us;lat_10us;lat_20us;lat_50us;lat_100us;lat_250us;lat_500us;lat_750us;lat_1000us;lat_2ms;lat_4ms;lat_10ms;lat_20ms;lat_50ms;lat_100ms;lat_250ms;lat_500ms;lat_750ms;lat_1000ms;lat_2000ms;lat_over_2000ms;disk_name;disk_read_iops;disk_write_iops;disk_read_merges;disk_write_merges;disk_read_ticks;write_ticks;disk_queue_time;disk_util

 
 
 Trace file format
 
 
 Trace file format


@@ -3531,7 +3563,7 @@ If windowed logging is enabled and :option:`log_max_value` is set, then fio logs
 maximum values in that window instead of averages.  Since 'data direction' and
 'offset' are per-I/O values, they aren't applicable if windowed logging is enabled.
 
 maximum values in that window instead of averages.  Since 'data direction' and
 'offset' are per-I/O values, they aren't applicable if windowed logging is enabled.
 

-Client/server
+Client/Server

 -------------
 
 Normally fio is invoked as a stand-alone application on the machine where the
 -------------
 
 Normally fio is invoked as a stand-alone application on the machine where the